1 files changed, 97 insertions, 0 deletions
diff --git a/devtools/client/netmonitor/src/connector/har-metadata-collector.js b/devtools/client/netmonitor/src/connector/har-metadata-collector.js
new file mode 100644
index 0000000000..c0227065a5
--- /dev/null
+++ b/devtools/client/netmonitor/src/connector/har-metadata-collector.js
@@ -0,0 +1,97 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const {
+  TYPES,
+} = require("resource://devtools/shared/commands/resource/resource-command.js");
+
+/**
+ * This collector class is dedicated to recording additional metadata necessary
+ * to build HAR files. The actual request data will be provided by the
+ * netmonitor which is already monitoring for requests.
+ *
+ * The only purpose of this class is to record additional document and network
+ * events, which will help to assign requests to individual pages.
+ *
+ * It should be created and destroyed by the main netmonitor data collector.
+ */
+class HarMetadataCollector {
+  #commands;
+  #initialTargetTitle;
+  #navigationRequests;
+  #targetTitlesPerURL;
+
+  constructor(commands) {
+    this.#commands = commands;
+  }
+
+  /**
+   * Stop recording and clear the state.
+   */
+  destroy() {
+    this.clear();
+
+    this.#commands.resourceCommand.unwatchResources(
+      [TYPES.DOCUMENT_EVENT, TYPES.NETWORK_EVENT],
+      {
+        onAvailable: this.#onResourceAvailable,
+      }
+    );
+  }
+
+  /**
+   * Reset the current state.
+   */
+  clear() {
+    this.#navigationRequests = [];
+    this.#targetTitlesPerURL = new Map();
+    this.#initialTargetTitle = this.#commands.targetCommand.targetFront.title;
+  }
+
+  /**
+   * Start recording additional events for HAR files building.
+   */
+  async connect() {
+    this.clear();
+
+    await this.#commands.resourceCommand.watchResources(
+      [TYPES.DOCUMENT_EVENT, TYPES.NETWORK_EVENT],
+      {
+        onAvailable: this.#onResourceAvailable,
+      }
+    );
+  }
+
+  getHarData() {
+    return {
+      initialTargetTitle: this.#initialTargetTitle,
+      navigationRequests: this.#navigationRequests,
+      targetTitlesPerURL: this.#targetTitlesPerURL,
+    };
+  }
+
+  #onResourceAvailable = resources => {
+    for (const resource of resources) {
+      if (resource.resourceType === TYPES.DOCUMENT_EVENT) {
+        if (
+          resource.name === "dom-complete" &&
+          resource.targetFront.isTopLevel
+        ) {
+          this.#targetTitlesPerURL.set(
+            resource.targetFront.url,
+            resource.targetFront.title
+          );
+        }
+      } else if (resource.resourceType === TYPES.NETWORK_EVENT) {
+        if (resource.isNavigationRequest) {
+          this.#navigationRequests.push(resource);
+        }
+      }
+    }
+  };
+}
+
+exports.HarMetadataCollector = HarMetadataCollector;